Figure 2.

NP₃ binds up to 3 Z monomers. NP and Z were incubated in a 1:10 molar ratio and subjected to nMS in a 150 mM ammonium acetate solution at pH 7.5. (A) Overview spectrum recorded with a 50 V acceleration. Two peak series are observable between 1000 and 4000 m/z (corresponding to the Z protein) and between 5500 and 7000 m/z (NP₃ complexes). Zoom to the NP₃ 29+ charge state (B) without and (C) with Z protein. Several new species corresponding to NP-Z complexes are recorded. (D) CID-MS/MS at 100 V acceleration for NP₃-Z (31+ charge state), NP₃–2xZ (33+ charge state), and NP₃-3xZ (34+ charge state). CID products correspond to masses for Z (11.35 ± 0.04 kDa), NP₃ (189.56 ± 0.03 kDa), NP₃-Z (201.00 ± 0.09 kDa), and NP3–2xZ (212.37 ± 0.13 kDa). The charge states of the most abundant peaks are indicated.